Ticking noise

Whole day today i spent my day figuring whats wrong with my computer. It was making a real annoying/ticking noise that it bothers me. Therefore, i decided to open my computer case and see if there is something loose inside like(cords). I didnt see anything laying or loose. So i decided to unhooked the fan and power supply and free them from dust. It was grubby of dust[gross]. I took them apart and put them all together after cleaning them. I used cotton buds,vacuum, and brush to to clean them. Doing this process i accidentally broke my computer case now it does not closed all the way..what a day.
Unfortunately, the annoying noise is still going on. I called someone to help me about this trouble and he told me to unplugged the cord connecting the fan and mobo. I did that but still the trouble is still there. Now i am wondering if it is my power supply or fan making this noise. I pretty much did what i could to fix the problem. Now i have to see if it is my HD making all this noise. I am so upset that i dont even want to bother about this...grahhhh. It is pissing me off because i have been studying for this and i cant seem to figure out..so disappointed. What else i can do. I have taken everything out and put them back on and the trouble still there. Can someone give me an idea what it could be..Thank you.